1. Field of the Invention
This invention relates to jet pumps that are used to lift fluids such as water and oil from the interior of an oil well. Pumps of this type utilize a nozzle and a venturi tube to create a pressure drop which can draw fluid from a location in the well below the pump. The power fluid and produced fluid from the well are then comingled in a mixing tube and diffuser where the pressure is increased to a point where the power and produced fluids are forced to the surface of the well where the produced fluids can be separated.
2. Description of Related Art
Jet pumps as described above are known that include a subassembly of the pump to be circulated back to the surface for servicing for example, by reverse flow of the power fluid. In normal operation, power fluid under pressure is pumped down a tubular positioned within the well casing and the mixture of the power fluid and produced fluid is conveyed upwardly in the annulus between the tubular and the casing. To pump back certain subassemblies for service, for example, the power fluid is pumped down the annulus and forces the subassembly up through the tubular.
Also, jet pumps are known that can be operated in a direct flow or reverse flow configuration. The nozzle assembly can be retrieved at the surface and replaced by a reverse flow nozzle arrangement. In this configuration, it is necessary to provide a stop mechanism to prevent the nozzle assembly from being pumped back to the surface in the reverse flow position. The stop mechanism may include a plurality of dogs on the pump housing which extend into an annular pocket found on the interior surface of a sub that surrounds the pump housing. A conventional tool may be used to pivot the dogs out of the pocket when it is desired to remove the inner components of the jet pump.
However, the prior art does not include an entire jet pump assembly that can be installed in the reverse flow mode and subsequently removed from the tubular string without the use of a wire line.